In silico studies on the molecular interactions of steroid hormones and steroid hormone mimicking drugs in the androgen receptor binding cleft - Implications for prostate cancer treatment.

Occupancy of prostate cancer (PCa) cell androgen receptors (AR) signals proliferation, therefore testosterone biosynthesis inhibitors and AR antagonists are important PCa treatments. Conversely, androgen mimics (e.g., prednisone) used in management of PCa might cause proliferation. The balance between PCa proliferation and inhibition predicts treatment success. We used in silico molecular modelling to explore interactions between ARs, androgens (testosterone, dihydrotestosterone (DHT)) and drugs used to treat (bicalutamide) and manage (dexamethasone, prednisone, hydrocortisone) PCa. We found that hydrogen (H-) bonds between testosterone, DHT and Arg752, Asn705 and Thr877 followed by ligand binding cleft hydrophobic interactions signal proliferation, whereas bicalutamide antagonism is via Phe764 interactions. Hydrocortisone, dexamethasone and prednisone H-bond Asn705 and Thr877, but not Arg752 in the absence of a water molecule. Studies with a bicalutamide agonist AR mutation showed different amino acid interactions, indicating testosterone and DHT would not promote proliferation as effectively as via the native receptor. However, hydrocortisone and bicalutamide form Arg752 and Asn705 H-bonds indicating agonism. Our results suggest that as PCa progresses the resulting mutations will change the proliferative response to androgens and their drug mimics, which have implications for the treatment of prostate cancer.

Sixty years of conjecture over a urinary biomarker: a step closer to understanding the proposed link between anxiety and urinary pyrroles.

OBJECTIVE: For over 60 years there has been conjecture about the identity of an Ehrlich's test positive pyrrole (Mauve Factor) reputed to be a biomarker for psychological disorders, including anxiety. We reviewed studies that attempt to identify Mauve Factor and subjected authentic standards of the 2 main candidates, kryptopyrrole and hydroxypyrrole, to the Ehrlich's reaction. METHODS: Modified Ehrlich's test for kryptopyrrole and hydroxypyrrole were applied to urine samples from 10 volunteers, anxious and nonanxious. RESULTS: Based on the mechanistic chemistry of Ehrlich's reaction and reactions of the 2 compounds, Mauve Factor cannot be hydroxypyrrole. Analyses of urine samples from volunteers, identified by the Generalized Anxiety Disorder - 7 item scale (GAD-7 ≥10; n = 5) and control urine samples (GAD-7 <10; n = 5) using a kryptopyrrole calibration graph, show that concentrations are similar in both groups. CONCLUSION: Kryptopyrrole may be the elusive Mauve Factor. Its possible origin from stercobilin via gut microbiome-mediated metabolism, its link to gut-mediated neurological effects via γ-aminobutyric acid (GABA) receptors, and its predicted interaction with Zn2+ and consequent impact on zinc homeostasis are discussed. The GAD-7 scale does not differentiate between state and trait anxiety and as such, the minimal difference in pyrrole levels between volunteer groups requires further study.

Could Microplastics Be a Driver for Early Onset Colorectal Cancer?

Introduction: The incidence of colorectal cancer in those under 50 years of age (early onset colorectal cancer (EOCRC)) is increasing throughout the world. This has predominantly been an increase in distal colonic and rectal cancers, which are biologically similar to late onset colorectal cancer (LOCRC) but with higher rates of mucinous or signet ring histology, or poorly differentiated cancers. The epidemiology of this change suggests that it is a cohort effect since 1960, and is most likely driven by an environmental cause. We explore the possible role of microplastics as a driver for this change. Review: The development of sporadic colorectal cancer is likely facilitated by the interaction of gut bacteria and the intestinal wall. Normally, a complex layer of luminal mucus provides colonocytes with a level of protection from the effects of these bacteria and their toxins. Plastics were first developed in the early 1900s. After 1945 they became more widely used, with a resultant dramatic increase in plastic pollution and their breakdown to microplastics. Microplastics (MPs) are consumed by humans from an early age and in increasingly large quantities. As MPs pass through the gastrointestinal tract they interact with the normal physiological mechanism of the body, particularly in the colon and rectum, where they may interact with the protective colonic mucus layer. We describe several possible mechanisms of how microplastics may disrupt this mucus layer, thus reducing its protective effect and increasing the likelihood of colorectal cancer. Conclusions: The epidemiology of increase in EOCRC suggests an environmental driver. This increase in EOCRC matches the time sequence in which we could expect to see an effect of rapid increase of MPs in the environment and, as such, we have explored possible mechanisms for this effect. We suggest that it is possible that the MPs damage the barrier integrity of the colonic mucus layer, thus reducing its protective effect. MPs in CRC pathogenesis warrants further investigation. Future directions: Further clarification needs to be sought regarding the interaction between MPs, gut microbiota and the mucus layer. This will need to be modelled in long-term animal studies to better understand how chronic consumption of environmentally-acquired MPs may contribute to an increased risk of colorectal carcinogenesis.

Healthcare workers' knowledge and attitudes towards sterilization and reuse of medical devices in primary and secondary care public hospitals in Nepal: A multi-centre cross-sectional survey.

BACKGROUND: Healthcare facilities reprocess and sterilize reusable medical devices before each invasive clinical procedure, such as surgery, to prevent person-to-person or environmental transmission of pathogens through medical devices. We conducted a nationwide multi-centre cross-sectional survey in primary and secondary-care public hospitals in Nepal to assess the knowledge and attitudes of healthcare workers towards sterilization and reuse of medical devices. METHODS: We carried out a multi-centre cross-sectional survey comprising eleven primary-care (two district-level and nine district hospitals) and two secondary-care (zonal hospitals) public hospitals which covered all seven provinces of Nepal. Survey questionnaires were distributed to 234 healthcare workers including doctors, nurses, paramedics, and office assistants (involved in medical device reprocessing); 219 (93.6%) returned the completed questionnaire. Descriptive analyses of demographic information, knowledge and attitude responses of survey participants were performed. Logistic regression and ordinal regression models for complex samples were used to investigate associations between responses and independent variables. RESULTS: Except for a few areas, more than 70% of healthcare workers had proper knowledge about different aspects of sterilization and reuse of medical devices. Paramedics and office assistants were less likely to have the correct knowledge in different aspects compared to nurses. Permanent staff were more likely to give correct answers to some knowledge questions compared to temporary staff. Previous infection control training was positively associated with correct responses to some knowledge items. Most of the healthcare workers had positive attitudes towards different aspects of sterilization and reuse of medical devices, and nurses were more likely to have positive attitudes compared with other staff categories. CONCLUSIONS: Most of the healthcare workers had correct knowledge and positive attitudes towards most areas of sterilization and reuse of medical devices. However, they need proper education and training in some areas such as sterilization procedures, storage of sterilized devices, prion decontamination and standard precautions.

Quality of water for reprocessing of medical devices in healthcare facilities in Nepal.

Reusable medical devices are decontaminated and sterilized often many times by healthcare facilities across the globe. Reprocessing of medical devices comprises several processes and water plays an important role in some of these, including cleaning and steam sterilization. The water used is required to have certain qualities to ensure the effectiveness of the processes. In this short communication, we report findings of our study which measured quality parameters (pH, total hardness) for water used for medical device reprocessing in 13 primary and secondary care public hospitals in Nepal. The mean pH of water used for reprocessing of medical devices varied from 6.48 to 8.05 across the hospitals whereas the mean total hardness of water varied from 5.93 to 402.50 mg/L CaCO3. Although the range of the mean water pH across hospitals fell within the recommended range, many of the hospitals had mean total hardness higher than recommended for cleaning medical devices. None of the hospitals had mean total hardness suitable for using as feed-water for steam generation. Public hospitals in Nepal should have appropriate water treatment systems so that the recommended water quality can be achieved to ensure effective decontamination and reprocessing of medical devices.

Compliance of primary and secondary care public hospitals with standard practices for reprocessing and steam sterilization of reusable medical devices in Nepal: findings from nation-wide multicenter clustered audits.

BACKGROUND: Reusable medical devices in healthcare facilities are decontaminated and reprocessed following standard practices before each clinical procedure. Reprocessing of critical medical devices (those used for invasive clinical procedures) comprises several processes including sterilization, which provides the highest level of decontamination. Steam sterilization is the most used sterilization procedure across the globe. Noncompliance with standards addressing reprocessing of medical devices may lead to inadequate sterilization and thus increase the risk of person-to-person or environmental transmission of pathogens in healthcare facilities. We conducted nationwide multicenter clustered audits to understand the compliance of primary- and secondary-care public hospitals in Nepal with the standard practices for medical device reprocessing, including steam sterilization. METHODS: We developed an audit tool to assess compliance of hospitals with the standard practices for medical device reprocessing including steam sterilization. Altogether, 189 medical device reprocessing cycles which included steam sterilization were assessed in 13 primary and secondary care public hospitals in Nepal using the audit tool. Percentage compliance was calculated for each standard practice. Mean percentage compliances were obtained for overall primary and secondary care hospitals and for each hospital type, specific hospital and process involved. RESULTS: For all primary and secondary care hospitals in Nepal, the mean percentage compliance with the standard practices for medical device reprocessing including steam sterilization was 25.9% (95% CI 21.0-30.8%). The lower the level of care provided by the hospitals, the lower was the mean percentage compliance, and the difference in the means across the hospital types was statistically significant (p < 0.01). The mean percentage compliance of individual hospitals ranged from 14.7 to 46.0%. The hospitals had better compliance with the practices for cleaning of used devices and transport and storage of sterilized devices compared with the practices for other processes of the medical device reprocessing cycle. CONCLUSION: The primary and secondary care hospitals in Nepal had poor compliance with the standard practices for steam sterilization and reprocessing of medical devices. Interventions to improve compliance of the hospitals are immediately required to minimize the risks of person-to-person or environmental transmission of pathogens through inadequately reprocessed medical devices.

Are over-the-counter fish oil supplements safe, effective and accurate with labelling? Analysis of 10 New Zealand fish oil supplements.

AIM: Fish oil supplements are regulated in New Zealand under the Dietary Supplement Regulations (Section 42, Food Act 1981) and therefore are not subject to the same level of scrutiny and regulations as medicines. We investigated accuracy of labelling, stated health benefits of fish oil supplements sold in New Zealand, and risks relating to possible mercury content. METHOD: The amounts of omega-3 fatty acids contained per capsule were determined by an independent laboratory using gas chromatography on 10 of the most popular over-the-counter fish oil supplements sold in New Zealand and were compared with amounts stated on product labels. Information on doses recommended to achieve a specific health benefit were taken from the 10 labels as well as the company websites. These recommended doses were compared with published recommended doses identified as being effective in those health areas stipulated on the labels, based on either systematic reviews, meta-analyses and/or consensus statements. Mercury was analysed by an independent laboratory using inductively coupled plasma mass spectrometry. RESULTS: The actual amounts of EPA and DHA per capsule in 90% of the over-the-counter fish oil supplements analysed were within 10% of the amount stated on the product labels. Only one product was greater than 10% below the stated dose on the label. All products suggested benefit across heart, brain and joint health and all but two products stated a range of capsules required to achieve that health benefit (eg, 2-6 capsules). Based on the maximum number of capsules recommended (which ranged from 3-6 capsules), only three products would likely confer the dose identified as optimal for achieving a health benefit across all three health areas. Only two products recommended doses that would likely confer a health benefit both at the minimum and maximum number of capsules. More products would likely benefit brain and heart health than joint health. Mercury was not detected in any sample. CONCLUSIONS: It is reassuring that the doses of 90% of the products were accurate and that mercury was not detected in any sample; however, less than a third of the supplements would likely confer all the health benefits stated, even at the highest recommended daily doses. This paper has highlighted the ongoing challenges associated with the regulation of "health claims" associated with dietary supplements in New Zealand. Indeed, the literature on health effects is contradictory at best. Clearer definitions of the types of health statements that can be made and the research necessary to support them requires regulatory clarification.

Dietary isoflavone-induced, estrogen receptor-ß-mediated proliferation of Caco-2 cells is modulated by gallic acid.

Dietary isoflavones and their biotransformation products (from food fermentation) are estrogen mimics which activate estrogen receptors (ER)α and ERß. In silico molecular modelling is used to determine theoretical binding energies of genistein, daidzein and hydroxylated biotransformation products, and to investigate structure-binding energy relationships with ERß. Results suggest that ligand hydroxyl arrangement determines binding energy and influences binding affinity. Caco-2 cells (ERß expressing) are used to study the proliferative effect of genistein, daidzein and their hydroxylated biotransformation products. Isoflavones/biotransformation products showed weaker enhancement of Caco-2 proliferation than 17ß-estradiol. The EC50s of isoflavones/biotransformation products agreed with in silico-predicted binding affinity order. Hydroxylated biotransformation products studied showed greater Caco-2 proliferative effects than the parent isoflavones except 8-hydroxygenistein, probably due to unfavourable ERß interactions caused by 8-hydroxygenistein's extra hydroxyl. Caco-2 pre-treatment with UDP-glucose dehydrogenase inhibitor gallic acid promoted genistein/8-hydroxygenistein-mediated proliferation. This is probably due to a reduced isoflavone glucuronidation to form low estrogenicity glucuronides. Findings are discussed in the context of dietary isoflavones/gallic acid and effects on proliferation of ERß-expressing gut cancer cells.

Effectiveness of steam sterilization of reusable medical devices in primary and secondary care public hospitals in Nepal and factors associated with ineffective sterilization: A nation-wide cross-sectional study.

BACKGROUND: Inadequate sterilization of reusable medical devices can lead to healthcare associated infections (HAIs) through person-to-person or environmental transmission of pathogens. Autoclaving (steam sterilization) is most commonly used for sterilizing medical devices in healthcare facilities. We conducted a nation-wide cross-sectional study to evaluate the effectiveness of steam sterilization practices in primary and secondary care public hospitals in Nepal and to identify factors associated with ineffective sterilization. METHODS: Using a stratified clustered random sampling, 13 primary- and secondary-care public hospitals in Nepal were selected. 189 steam sterilization cycles from these hospitals were evaluated for their effectiveness using self-contained biological indicators, class-5 chemical indicators, autoclave indicator tape and physical parameters. Information about the hospitals and the types of autoclaves being used was also collected. Data were analysed to estimate the proportion of ineffective steam sterilization cycles. Logistic regression was used to identify factors associated with ineffective sterilization. FINDINGS: In primary and secondary care public hospitals in Nepal, 71.0% (95% CI 46.8% - 87.2%) of the autoclave cycles were ineffective (i.e. showed positive results) when tested with biological indicators and 69.8% (95% CI 44.4% - 87.0%) showed 'reject' results with class 5 chemical indicators. There was no statistically significant difference in proportions showing positive or reject results by hospital types for either biological (p = 0.51) or class 5 chemical (p = 0.87) indicators. Autoclave type and pressure achieved during sterilization were statistically significantly associated with steam sterilization failures, adjusted for holding period, evenness of pressure and barrier system used. CONCLUSION: Primary and secondary care hospitals in Nepal have a high proportion of steam sterilization failure, indicating a risk of person-to-person transmission of pathogens through reusable medical devices. There is an urgent need to improve steam sterilization processes in these hospitals.

RETRACTED Are over-the-counter fish oil supplements safe, effective and accurate with labelling? Analysis of 10 New Zealand fish oil supplements.

RETRACTED.

Food flavonoid ligand structure/estrogen receptor-α affinity relationships - toxicity or food functionality?

In silico molecular modelling is used to study interactions between flavonoid phytoestrogens and estrogen receptor (ER)α. Twenty flavonoids from foods were studied; e.g., genistein from soy, naringenin from grapefruit, phloretin from pears, chrysin from oyster mushrooms. These potential ligands' molecular attributes and their spatial arrangements that favour binding to the ligand binding cleft (LBC) of ERα are identified, and Docking Scores calculated. The Docking Score order is the same as the estrogenicity order for 8 of the flavonoids studied in detail. The number and position of flavonoid ring hydroxyls influence the Docking Scores which might relate to ERα's bio-activity. Hydrophobic interactions between ligands and ERα are also important; the number of rotatable CC bonds in ligands likely affects the magnitude of hydrophobic interactions and ligand fit. Our findings suggest that flavonoids with diverse structural features could have different binding energies and binding affinities with ERα, which might confer different functionalities and toxicities.

Effectiveness of autoclaving in sterilizing reusable medical devices in healthcare facilities.

Medical devices are sterilized before being used for invasive clinical procedures such as surgery, to prevent pathogen transfer. Failure to sterilize medical devices properly presents a risk of healthcare-associated infections. Studies and reports have indicated that inadequately sterilized medical devices are one of the causes of a higher rate of healthcare-associated infections in developing countries. Steam sterilization (autoclaving) is the most widely used method for sterilization and is considered the most robust and cost-effective method for sterilization of medical devices. The effectiveness of steam sterilization can be measured using biological indicators. A literature search was undertaken to understand the effectiveness of autoclaving in sterilizing reusable medical devices in healthcare facilities across the globe. Studies using biological indicators for measuring the effectiveness of autoclaving were obtained. Failures of steam sterilization practices were identified and discussed as a means of identifying factors that might be associated with the ineffectiveness of steam sterilization practices between different countries. The number of studies measuring the effectiveness of steam sterilization is small, and few evaluate the effectiveness of steam sterilization specifically in developing countries. There are fewer studies on higher level healthcare facilities than dental facilities. More evidence about the effectiveness of autoclaving in healthcare facilities is needed to draw firm conclusions, but the data suggest that there are inadequacies in autoclave procedures and operator education.

The ketogenic diet as a potential treatment and prevention strategy for Alzheimer's disease.

The prevalence of Alzheimer's disease, a chronic neurodegenerative condition, is increasing as is the need for effective treatments and preventions. The underlying pathology of Alzheimer's is not yet fully understood, so existing research has focused on understanding the prominent features of the disease. These include amyloid plaques, which accumulate in the brains of those with Alzheimer's disease; impaired glucose metabolism; and neuronal cell death. Emerging evidence suggests that a low-carbohydrate, high-fat ketogenic diet may help to mitigate the damage associated with these pathologies. The ketogenic diet could alleviate the effects of impaired glucose metabolism by providing ketones as a supplementary energy source. In addition, this diet may help to reduce the accumulation of amyloid plaques while reversing amyloid ß toxicity. Research has begun to identify early underlying mechanisms in Alzheimer's disease that could be targeted by new prevention strategies. Glycation of the ApoE protein leads to impaired transportation of important lipids, including cholesterol, to the brain, resulting in lipid deficiencies that could explain progression to the later pathologies of the disease. In this review, we hypothesize that the ketogenic diet could be an effective treatment and prevention for Alzheimer's disease, but both ketone production and carbohydrate restriction may be needed to achieve this.

Intimate estrogen receptor-α/ligand relationships signal biological activity.

How does estrogen receptor-α bind its natural ligands - estrogens? How can other molecules mimic estrogens and elicit different estrogenic responses? The answers lie in a complex and intimate chemical biology between ligands and receptor. This delicate interaction at the ligand binding cleft signals, via conformational change, exposure of a specific new charge topography at a second site (Activation Function-2). This, in turn, attracts a regulatory protein which modulates gene expression and controls biological activity.

Measurement of kidney cadmium in embalmed New Zealand cadavers.

Cadmium (Cd) is a toxic (carcinogenic) metal found in food because of its presence in the environment. New Zealand has elevated levels of Cd in soil due to the long term use of Cd-containing phosphate fertilisers. It is therefore likely that New Zealanders have a high Cd body burden which might have health implications. The aims of this study were to determine whether Cd levels in kidney cortex samples are affected by the embalming process and whether kidney cortex samples from embalmed cadavers (e.g. those used for medical student teaching purposes) can be used as a reliable indicator of Cd body burden. Kidney cortex samples from cadavers preserved with different embalming fluids were analysed for Cd by inductively coupled plasma mass spectrometry (ICP-MS). A perfused pig kidney model was used to investigate the effects of embalming on kidney cortex Cd levels. We report considerable variability in Cd levels in kidney cortex samples according to the embalming fluid used; this suggests that the embalming fluid influences tissue Cd concentrations. All pig kidney model perfusions resulted in leaching of Cd from the kidney cortex. We conclude that analysis of Cd in embalmed tissues does not give a reliable indication of in-life Cd levels.

Are the amounts of vitamins in commercially available dietary supplement formulations relevant for the management of psychiatric disorders in children?

AIM: To investigate whether micronutrient supplements shown through research to have perceived benefits in the treatment of psychological/psychiatric symptoms in children have similar vitamin ingredients and doses to over-the-counter dietary supplements. METHODS: We conducted a systematic review to identify studies that used micronutrients for the treatment of psychological/psychiatric symptoms in children with documented benefits; 13 different supplements were identified that included vitamin ingredients. They were compared with the vitamin composition of 22 over-the-counter child-targeted supplements available in New Zealand. RESULTS: The vitamin ingredients were comparable across the research and commercially available supplements. However, the median vitamin daily doses in research supplements were found to be greater than those of over-the-counter supplements, with most mean differences being significant, including vitamins B1, B3, B6, B7, B12, C and D (p<0.05), B5 and B9 (p<0.001), but not vitamins A or B2. CONCLUSIONS: Micronutrient supplements found to show potential benefit in research with a focus on improving psychological/psychiatric symptoms in children have a significantly greater vitamin dose than over-the-counter supplements. Therefore, the results found in micronutrient research studies cannot be extrapolated to over-the-counter supplements. Comparing the myriad ingredients and dosages in micronutrient supplements is, however, a complex process and further investigation is required to understand fully the importance of our findings.

New Zealand Malayan war veterans' exposure to dibutylphthalate is associated with an increased incidence of cryptorchidism, hypospadias and breast cancer in their children.

It is well known that the endocrine-disrupting chemical (EDC) dibutylphthalate (DBP) inhibits testosterone synthesis and can lead to feminisation in male laboratory animals. Moreover, it has long been speculated that human exposure would result in the similar effects, but this is difficult to study because specific human exposure cohorts are rare. We report increases in the incidences of hypospadias (p<0.05), cryptorchidism (p<0.05) and breast cancer (p<0.05) in the children of New Zealand soldiers who served in Malaya (1948-1960) and were exposed to DBP applied daily to their clothing as an acaricide to prevent tick-transmitted bush typhus. In addition, we modelled absorption of DBP from the soldiers' clothing and using published data for skin absorption, and calculated a large theoretical absorbed dose of 64 mg/kg body weight/day which is similar to DBP's lowest observed adverse effect level (LOAEL) of 50 mg/kg body weight/day and thus indicates a biological effect is possible. This is the first report of a multigenerational developmental effect following DBP exposure in human males.